Developing multivariate models for predicting the level of dissatisfaction due to a specific metro noise masked with four specific water sounds

Abstract

Incorporating pleasant sounds into traffic noises is an important design strategy to optimize noise perception. However, as the previous studies based on the auditory masking method mainly focused on road traffic or aircraft noises, there is a lack of research on alleviating the negative perceptions due to metro noise by adding other sounds. Accordingly, this study analyzed the regulation mechanisms of four specific water sounds (fountain, stream, water-drop and waterfall sounds) on the dissatisfaction due to a specific metro noise and established the multivariate models to predict the dissatisfaction level due to combined metro-water sounds. Seventy-nine subjects participated in the experiment and were exposed to a series of acoustic samples before being asked to cast their negative perception votes. The results suggested that the dissatisfaction with metro noise could be improved by adding the four types of water sounds, among which the capability of water-drop sound was the strongest, followed by the fountain and stream sounds, and the waterfall sound was the least effective. Besides, in order to reduce the dissatisfaction level at the global sound pressure levels (SPLs) of 60 and 65dBA, the SPL of metro noise should be no more than 3 dBA higher than that of water sound, and a water signal-to-noise ratio (WSNR) of 6 dBA was most desirable. Furthermore, among the considered models (energy summation model, independent effects model and energy difference model), the independent effects model, which fitted the dissatisfaction level data moderately, yielded the relatively highest coefficients of determination after one relevant acoustic factor (WSNR Threshold) and personality traits (gender and sensitivity) were added. It is worth noting that a single metro noise and a single sample for each type of water sound were selected and their combined sounds were studied, thus, this study could be considered as a preliminary work and the results and applicability have limitations.